Explain SQL Logic and Edge Cases | Dataford Interview Questions

How would you explain your SQL query logic and edge cases during an interview?

Using the provided orders table, explain the query that returns the five customers with the highest completed, positive-value order totals. Address NULL values, zero and negative amounts, excluded statuses, ties, and customers without valid names.

Output

One row per qualifying customer with customer_name and total_spent.
Include only completed orders with positive amounts and non-NULL customer names.
Sort by total_spent descending, then customer_name ascending, and return the first five customers.

Schema

orders

Column	Type	Description
order_idPK	INT	Unique order identifier
customer_name	VARCHAR(100)	Customer name associated with the order
status	VARCHAR(20)	Order processing status
amount	DECIMAL(10,2)	Order amount
order_date	DATE	Date the order was placed

Your question is Explain SQL Logic and Edge Cases. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

How would you explain your SQL query logic and edge cases during an interview?

Output

One row per qualifying customer with customer_name and total_spent.
Include only completed orders with positive amounts and non-NULL customer names.
Sort by total_spent descending, then customer_name ascending, and return the first five customers.

Schema

orders

Column	Type	Description
order_idPK	INT	Unique order identifier
customer_name	VARCHAR(100)	Customer name associated with the order
status	VARCHAR(20)	Order processing status
amount	DECIMAL(10,2)	Order amount
order_date	DATE	Date the order was placed

Your question is Explain SQL Logic and Edge Cases. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.